CVE-2026-47075: CR/LF injection in query parameter in hackney

Vulnerability summary

CVE-2026-47075 is a high (CVSS 7.5) vulnerability in benoitc hackney. EPSS estimates a 0.48% chance of exploitation in the next 30 days, higher than 41.3% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 25-05-2026
   PublishedVulnerability first disclosed.
2. 24-07-2026
   Last modifiedVulnerability information updated.

Description

Improper Neutralization of CRLF Sequences vulnerability in benoitc hackney allows HTTP Request Splitting. hackney does not percent-encode carriage return (\r) or line feed (\n) characters in the URL query component before constructing the HTTP/1.1 request target. Characters outside the grammar defined in RFC 3986 Section 3.4 must be percent-encoded, but hackney_url:make_url/3 passes the query binary directly without validation or escaping. An attacker who can control all or part of a URL passed to hackney can inject raw CRLF sequences into the query string, which are then sent as HTTP line breaks in the request target. This enables injection of arbitrary HTTP headers or splitting of the HTTP request. This issue affects hackney: from 0.13.1 before 4.0.1.

• CWE-93Improper Neutralization of CRLF SequencesThe product uses CRLF (carriage return line feeds) as a special element, e.g. to separate lines or records, but it does not neutralize or incorrectly neutralizes CRLF sequences from inputs.